Printing form and method of producing same



Se'pt" 1927' v E. BALLARD 1'643'046 PRINTING FORM AND METHOD OFPRODUCING SAME Original Filed March 19, 1926 Zlnvc 11 Too Patented Sept.20, 1927.

UNITED STATES manner :1. BALLARD, or annexe,- camroanm. H

rnnv'rme roar: AND mn'rnon or rnonuome sans.

} v 1,643,046 PATENT OFFICE.

Application filed March 19, 1826, Serial No, 96,020. Renewed December 8,1926.

This invention relates to improvements in printing forms or surfaces foruse in photogravure, rotary photogravure and like processes and to anovel method of producing such forms or surfaces.

, Some of the printing forms heretofore proposed for use in the abovementioned processes have embodied a base on which there was deposited anexterior layer of metal adapted to receive the image to be repro ducedinsome instances, and, after the required reproductions had been made,such exterior layer would be removed by subjecting the form to anacidwhich would remove said layer. etching on the outer surface is removedby grinding, a process which is slow and costly and also reduces thecross section of the form.

, Removal of the outer etched surface by acid is costly, wasteful anduneven in re- *sult's. Removal by grinding is' slow and costly. Forthese reasons, the primary object contemplated by the present inventionconslsts in providinga novel printing form for photogravure or rotaryphotogravure processes, as well as a novel method of preparing such aform, the salient characteristic of the form being that the exteriorlayer, on which is received the engraved image. to bejprinted, may bespeedily removed from the permanent base without the use of acids or byslow and costly grinding. The improved process herein disclosed for theproduction of printing-forms provides a means of depositingby-electrolysls upon a metallic base, preferably cylindrical in form, alayer of metal preferably copper, in such a manner that the layer orcoating, though surrounding'the base and remaining in close contacttherewith by? reason of its own cylindrical and all-ernbracingform, canat any time bestrilpped from the base by peeling or tearing tcumferential ends of the base. The process also provides, in order tofurther guard against theremoval of the outer layer of metal until suchremoval is'desired, a seal or look for-a narrow marginalong the twocircumferential ends of the cylinder, said seal consisting of an actualmechanical union between the outer layer and'the base, eflected byelectrolytic action.

Referring to the figures of the drawing: Fig. 1 is a perspective view ofaprinting roll showing the use of my invention.

In other instances, the previous erefrom, beginning at the. cirby in thesolution and; known as the. anode, the revolving cylinder beingthe'cathode and.v

Fig. is an enlarged fragmentary sectional view thereof.

assure While the printing form may assume any desired shape, in so faras the (practice of 10 is a thin layer or coating of material 11 ofrelatively low .fusibility, preferably an alloy oftin, lead, cadmium andbismuth or other alloy of low fusibility, which is applied to base 10 byraising the temperature of base 10 to a higher degree than the meltingpoint of thealloy, and .then applying the same, using suitablefluxes,and wiping the alloy over-the entire useful surface of base 10,polishing off to a uniform mirror finish. Other suitable means commonissoldering practices can be utilized to apply and uniformly distributethe coating of alloy.

On the very thin layer 11 there is a plied an exterior coating 12 ofsome metal a apted to receive the images to be. printed. In actualpractice it is preferred to form said layer 12 of copper, the base 10 ofcopper or brass, an the intermediate layer of an alloy of lead, inbismuth and cadmium, or other 'alloy, in such proportions as will givean alloy melting point of about 202 degrees Fahrenheit.-

With the base -10 coated with this alloy of lead, tin, cadmium andbismuth, or other alloy, but with narrow margins at each end, 13 and 14,exposed and-presenting a portio'nof the base not covered with the alloy,the form is immersed in a plating solution composed of coppersulphate,water and sulphuric acid in approximate proportions of two pounds ofcopper sulphate and one half pound of sulphuric acid to one gallon ofwater, and kept in rapid uniform rotation, while'subje'cted to a currentofelectricity passing from a sheet of copper placed near.-

being" electrically connected with'the source of current'supply, thewhole being the arrangement commonly used in the electrode osition ofcopper.

nder such treatment, with brisk uniform rotation of the cylinder, the{very thin layer or coating 11 on the cylinder takes on a ableforprinting purposes such as before mentioned.

Although electro-deposited upon the coating 11, the layer 12 is notmechanically or otherwise attached thereto, it being a peculiar andrequisite characteristic of the alloy surface, that the thin layer ofeleotro-deposited copper 12, by reason of the electrochemical reactionswith the alloy during the electroplating as formerly noted, does notadhere to the surface of the alloy 11. The alloy at all times provides auniform conducting basic surface favoring the uniform distribution of acopper deposit from the moment the electrodeposition begins. While thisisolation of the copper surface might be accomplished between itself andany base by the interposition of a coating of grease, graphite, lacquer,or similar composition, such isolating results in extremely unevenplating, so that the final electrodeposited surface is not in conditionto, receive an etched image, without the customary and usual grindingand surfacing treatment.

The only mechanical connection established by the electrolytic action isat margins 13 and 14, where the copper conveyed from the anode hasfirmly attached itself to the uncovered copper or brass surfaces ofthese margins, acting as an airtight seal and'lock for the cylinder ofcopper that has been deposited upon the coating 11. Thus the layer 12,in intimate but not mechanical connection with layer 11, is further keptin close contact therewith by atmospheric pressure.

This lack of actual mechanical adhesion follows from the fact thatcoating 11, consisting of an alloy of low melting point, preferablylead, tin, bismuth and cadmium, or other metal, upon being placed in theelectroplating solution as heretofore mentioned and described, isaffected electrochemically by the plating solution preventing thecopper, conveyed to coating 11 "by electrolytic action, from enteringinto mechanical or actual connection or a dhesion with the alloy,although establishing a certain degree of union that maintains layer 12in close and intimate contact with coat 11. The electrically depositedcoat 12,'being cylindrical in form and sealed at each'end by the actualmechanical and airtight contacts at 13 and 14 becomes for all practicalpurposes an integral part of the printing form, and after slightpolishing and bufling is ready to receive the engraved image.

' After the form thus made has had the desired impression or imageplaced thereon andhas been used, if it is deslredto remove suchimpression and substitute another, the

seal at the ends 13 and 14 is broken by filing the circumferential edgeor by using other abrasive means when it will be found that layer 12superimposed upon coat 11 is not adhering thereto, and by starting witha knife edge or otherwise can be readily peeled off leaving coat 11ready to receive another electrodeposited layer 12, if coat 11 isundamaged. Otherwise coat- 11 is restored to proper condition by flowingon new metal as in common soldering practices, or as heretoforedescribed, after which the process may be repeated.

By being thus" able to easily and speedily remove the impressioncarrying layer 12, the present invention eliminates the grind- .ing downof the copper or other base and the surface of the base 10 is highlypolished and if coat 11 is evenly applied thereupon, and likewisepolished to a uniform mirror-like surface, it will follow that layer 12,preferably of copper, will go on smoothly, and only a comparatively thinlayer will be required for a printing surface. Thus the electricalenergy and time required in other processes for heavily coating the formwith copper and in subsequent turning and grinding back to uniform shapeand size is rendered unnecessary.

While I have herein specifically described and illustrated the preferredmethod of carrying out my invention, it will of course be understoodthat the same is capable of various modifications within the scope ofthe appended claims without departing from the s irit thereof. Forexample, while I preferab y employ the said metalic coating 11 in themanner herein described and illustrated, it will be obvious that theemployment of means other than this specific coating for preventingadherence of the layer 12 is within the scope of my invention.

Non-adhesion between the major portion of the outer layer and cylindermay be effected in numerous ways. Grease, oil, graphite or tarnishingand oxidizing reagents may be spread over the surface of and likeprocesses, consisting of providing on a permanent base a layer ofmaterial wit which the metal used thereon for printing llt) forms orsurfaces for use in photogravure will not permanently unite, andproviding a thin coating-of the required metal onthe said layer basebyelectrodepositing the said metal thereon, the coating being adapted tobe readily stripped from the base after use.

2. The method of producing printing forms or surfaces for use inphotogravure and like processes, consisting of "providing on the greaterportion of a permanent base a layer of material with which the metalused thereon for printing will not permanently unite, and providing athincoating of the required metal on the said layer base byelectrodepositing the said metal thereon,

the said metal and base uniting to form a seal at the portions notcovered by the said.

layer, and the coating being adapted tobe readily stripped from the baseafter use by. breaking this seal.

3. The method of producing cylindrical printing forms or surfaces foruse in photogravure and like processes, consisting of pro- .viding onthe greater portion of the cylindrical surface between the marginaledges thereof a layer of material with which the metal used thereon forprinting will not permanently unite, and providing a thin coating ofrequired metal on the said layer base by .e'lectrodepositing action, thecoating being freely removable from the cylinder ex-' 'ceptat themarginal portions where the metal unites with the base to form a seal.

4. The method ,of producing printing forms or surfaces for use inphotogravure and like processes which consists in applying to apermanent base a layer of material of. low fusibility which may bedistributed evenly over said permanent base and polished to a'mirrorsmoothness conforming to the surface of the base. itself. and coatingsaid layer with a metallic coating on which the image to be printed maybereceived.

' .5, The method of producing printing surfaces for use in photogravureand like processes which consists in applying to a permanent base alayer of metal of low melting point, and applying to said layer byelectrodeposition a layer of copper upon which the image to be printedmay be received.

6 The method of producing successive printing-surfaces for use inphotogravure and like processes which consists in. applying to apermanent base a layer of metal of low fusibility and electrodepositinga layer of copper thereon, said layer ofcopper adheringto the coating oflow fusibility with-. out having av mechanical connection there with,whereby the copper layer may atany time be stripped therefrom.

7. A printing form for use in photogramanent base, a thin layer of metalof low' relative fusibility on said base, and an exterior layerelectrodeposited thereon but not adhering to the inner layer of metaloflow 'fusibility, but adhering and entering into mechanicaLunion with thebase on its margin where there is no covering of metal of lowfusibility, said layer on the exterior of said metal of low fusibilitybeing removable .by' cutting or breaking those portionswhere adhesionexists between the exterior layer and the base and thereafter strippingaway the remaining portions which have not adhered to the metal of lowfusibility.

9. A printing form for use in photogra- I vure and like processesconsisting of apermanent base, a thin layer of metal of low fusibilityon said base, and an exterior layer of metal electrodeposited thereon,said exterior layer having a mechanical connection or union with saidbase and substantially free of the layer of metal of low fusibility.Whereby said exterior layer may be removed from the layer of metal .oflow fusibility without affecting the latter. 0

10. A printing form for use in photogravure and like processesconsisting of a prmanent base, a thin layer of metal of low fusibilityon said base andan exterior layer. covering said base and said metal oflow fusibility, there being a mechanical connection between said baseand exterior layer only'for retaining said layer on the form.

11. The method of producing. printing surfaces for use in photogravureand like processes which consists in applying to a permanent base acoating of an alloy of tin,

lead, cadmium and bismuth, and applying to said coating byelectrodeposition a layer of copper npon which an image to beprinted maybe received.

. ERNEST s. BALLARD,

